MOGADISHU, Somalia (AP) — The Latest on explosion in Somalia's capital (all times local):

5 p.m.

Police say the death toll has risen to 20 after a powerful truck bomb exploded in Somalia's capital, Mogadishu.

Capt. Mohamed Hussein says more than 15 people are injured.

The sound of ambulance sirens can be heard across the capital, and gunfire can be heard at the site of the blast.

The blast is the largest heard in Mogadishu in recent memory.

4:20 p.m.

A Somali police officer says a powerful explosion from a truck bomb has struck a busy road in the Somali capital and at least six people have been killed.

The blast is the largest heard in Mogadishu in recent memory.

Capt. Mohamed Hussein says the blast occurred Saturday as security forces were trailing the truck that had raised suspicions. A hotel apparently was targeted.

The blast at KM4 street in Hodan district occurred two days after the head of the U.S. Africa Command was in Mogadishu to meet with Somalia's president.

The U.S. military has stepped up drone strikes and other efforts this year against the Somalia-based al-Shabab extremist group, which often targets high-profile areas of Mogadishu with deadly bombings.

There was no immediate claim of responsibility for the blast.